Solubility data are reported for ethyl phenyl sulfide (EPS) and 2-chloroethyl ethyl sulfide (CEES) in CO 2 at temperatures from 25 to 100 o C. These two sulfide-based compounds are homomorphs for chemical warfare agents (CWAs). Both sulfide-CO 2 mixtures exhibit type-I phase behavior. The maximum in the 100 o C isotherm is approximately 2600psia for the CEES-CO 2 system and approximately 3400psia for the EPS-CO 2 system. The Peng-Robinson equation of state (PREOS) is used to model both sulfide-CO 2 mixtures as well as the phase behavior of the 2-chloroethyl methyl sulfide (CEMS)-CO 2 system previously reported in the literature. The Joback-Lydersen group contribution method is used to estimate the critical temperature, critical pressure, and acentric factor for the sulfides. Semi-quantitative estimates of the phase behavior are obtained for the CEES-CO 2 and EPS-CO 2 systems with a constant value of k i j , the binary interaction parameter, fit to the 75 o C isotherms. However, very poor fits are obtained for the 2-chloroethyl methyl sulfide-CO 2 system regardless of the value of k i j . On the basis of the high solubility of EPS and CEES in CO 2 , supercritical fluid (SCF)-based technology could be used to recycle or recover chemical warfare materials.